Origin and Maturity of Biomarker Aliphatic Hydrocarbon in Wondama Coal Indonesia

Organic geochemical characterization of Wondama coal samples from the Lengguru Folding Belt has been carried out through the study of its aliphatic hydrocarbon biomarkers. This study is to determine the origin, depositional environment and maturity of coal which is useful for determining the use of coal as an energy source. Aliphatic hydrocarbon biomarkers were identified by using gas chromatography-mass spectroscopy methods which showed the presence of n-alkane homologs (n-C15 - n-C33), which was dominated by n-C31. This indicates that the organic material originates from Angiosperms of terrestrial higher plants. The ratio of pristane to phytane (Pr/Ph) with value of 3.74 indicates that the Wondama coal is buried in an oxic depositional environment. The Carbon Preference Index (CPI) value of 7.82 and the C31αβS/(S + R) ratio of 0.27 indicate low maturity of Wondama coal and is classified into a sub-bituminous coal ranks.